对虾抗菌肽转基因水稻抑制饲料腐败和防治罗非鱼细菌病害的初步研究

探讨了以植物生物反应器开发利用抗菌肽类物质防治水产动物病害的效果和机理。以携带中国明对虾抗菌肽—对虾素3-2的转基因水稻米糠制作罗非鱼饲料,研究其对饲料腐败和吉富罗非鱼嗜水气单胞菌肠炎的抑制效果。通过测定米糠和饲料中的霉菌总数、细菌总数,发现水稻中表达的对虾素3-2能有效抑制饲料中的霉菌与细菌的繁殖,对于保持饲料品质具有显著的效果。选取规格一致、体质健壮的吉富罗非鱼,随机分成5组,每组3个重复,分别投喂含20%非转基因米糠的饲料与含不同质量比(10%、20%、30%)的转基因米糠的饲料。通过嗜水气单胞菌攻毒保护实验,结果发现,转基因米糠对罗非鱼嗜水气单胞菌肠炎具有显著的保护效果。对吉富罗非鱼的肠道主要微生物数量、中肠石蜡切片的进一步分析发现,摄食转基因米糠饲料组的罗非鱼肠道内大肠杆菌比例降低,乳酸菌比例提高,肠道微绒毛的结构完整性显著改善。由此推断抗菌肽转基因水稻的防病效果可能与肠道微生物的改变和对肠道结构的保护作用有关。但是石蜡切片发现过量添加转基因米糠(30%)也会导致吉富罗非鱼肠道上皮细胞损伤。

The effect of transgenic rice carrying antimicrobial gene of shrimp on feed spoilage and disease control in GIFT

Recently,more and more studies focus on the application of antimicrobial peptides to control bacterial diseases.For the first time,we report the using of plant bioreactor to develop functional feed additives in China.During our previous work,the penaeidin 3-2 gene from the shrimp Fenneropenaeus chinensis was transformed into rice Aichi ashahi.Tilapia feed which contained different levels of the transgenic or non-transgenic rice bran were tested for the effect of antimicrobial peptide expressed by rice plant on feed spoilage and disease control.The results of total bacteria and mold count showed that penaeidin 3-2 expressed in rice could effectively restrain growth of microorganisms in feed and bran.Another experiment was conducted to study the effect of different levels of transgenic rice bran(10%,20%,30%,respectively)on survival rate of tilapia infected by Aeromonas hydrophila.The results showed that survival rates of tilapia fed transgenic rice bran were significantly higher than those fed non-transgenic rice bran.In-depth study of the mechanism of enteritis control by transgenic bran was conducted by studying the gut microbial community and intestinal structure.The results showed that transgenic rice bran restrained growth of Escherichia coli,but enhanced lactic acid bacteria proliferation.And the intestinal structure of those fish fed transgenic bran was more intact than the control.So it is indicated that the disease control effect could be in connection with the change of gut microbial community and protective effect of intestinal structure.But it is noteworthy that the excessive addition of transgenic rice bran(30%)could cause epithelial cells degeneration.